Understanding the spreading of liquid drops on planar substrates is important in various applications (spraying, agriculture, painting and printing …) in which the dynamics of moving contact linesplays a major role. It involves the surface energies of all interfaces and hence the wettability of the materials. Surprisingly, Droplets spreading is observed on hydrophobic surfaceswhen both salt and surfactant are present in the solution.
This project consists of:
1 - Experimentally Measuring the spreading properties at different concentrations of different salts and surfactants.
2 - Studying the role of the wettability of the substrates.
3 - Quantifying the dynamics of the moving contact line by image analysis.
4 - Understand the role of NaCl on surfactant-surface interactions during droplet spreading.